MIAMI — In a likely blow to Bombardier’s anemic selling new CSeries, United will take delivery of 40 Boeing 737-700s to replace some of the smaller, older planes, operated by its regional carriers.

“We are continuing to move United forward and announced today we would take delivery of 40 new Boeing 737-700 aircraft, which will enter the fleet beginning in mid-2017.” commented United Airlines acting CEO Brett Hart, who also hinted that the new aircraft would up gauge the regional flying to the main line service standards. “These aircraft will give our customers the experience they want with first class seats, Economy Plus and Wi-Fi, while enabling us to reduce 50-seat flying” Hart said.

“Our customers have a preference for an improved travel experience, (…) and these aircraft are an efficient way to meet those needs while reducing 50-seat flying,” said Gerry Laderman, United’s acting chief financial officer.

United’s current fleet of 40 Boeing 737-700 seat 118 passengers, with 12 business class, 40 Economy Plus and 66 Standard Economy seats. The Chicago-based carrier said it plans to replace more than half of the 50-seat regional jets in its fleet by 2019.

This announcement represents a major setback for Bombardier and its troubled CSeries program, which has been seeking potential customers beyond the current order book standing at 243 planes. Last November, Bombardier’s sales team had been courting United, and showed the aircraft off to the airline’s senior management team and employees as part of a demonstration tour to prospective customers in the North America.

On the other hand, Delta is considered a strong potential buyer in light of positive comments made by its President Ed Bastian in an earnings call yesterday, admitting that the Atlanta-based carrier is taking “a serious look” to the aircraft.